CHAPTER - 6 TISSUES

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CHAPTER - 6TISSUES
CLASS - IX MADE
BY - MANAS MAHAJAN SCHOOL
- K.V. GANESHKHIND PUNE-7

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1) Tissues -

• Tissue is a group of cells having similar
  structure and function.
• In plants and animals groups of cells
  called tissues carry out
• specific functions.
• Eg - In human beings the cells of the
  muscular tissue contract and
• relax and help in movements.
• In plants the cells of the vascular
  tissue conduct water and food
• from one part of the plant to the
  other.

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2) Differences between plant and animal tissues
-

• a) Plant tissues -
• i) Plants do not move from place to place.
  Most of the cells and
• tissues in plants provide mechanical support
  and strength. So most
• of the tissues consists of dead cells
  because they provide
• mechanical support and strength to the
  plant.
• ii) The growth of plants takes place only in some
  regions. So plants
• have tissues called meristematic tissues
  which divide and help in
• growth and permanent tissues which do not
  divide.
• b) Animal tissues -
• i) Animals move from place to place and need
  more energy than
• plants. So most cells and tissues in animals
  are living cells.
• ii) The growth of animals is more uniform so
  animals do not have
• separate dividing and non dividing cells.
  Animals have organs
• having specialised functions. So the organs
  have specialised
• tissues.

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3) Plant tissues -

• Plant tissues are of two main types. They
  are Meristematic tissues and
• Permanent tissues.
• i) Meristematic tissues - are of three types.
  They are Apical meristematic
• tissues, Intercalliary meristematic tissues
  and Lateral meristematic tissues.
• ii) Permanent tissues - are of two types . They
  are Simple permanent tissues
• and Complex permanent tissues. Simple
  permanent tissues are of three
• types. They are Parenchyma, Collenchyma and
  Sclerenchyma. Complex
• permanent tissues are of two types. They are
  Xylem and phloem.
• 
  Plant tissues
• Meristematic tissues
  Permanent tissues
• Apical Intercalliary Lateral
• meristematic meristematic meristematic
• tissues tissues tissues
• Simple
  permanent Complex
  permanent
  
• 
  tissues
  tissues

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a) Meristematic tissue -

• Meristematic tissues are found in the growing
  regions of the plant like the tips of root, stem
  and branches. They divide continuously and help
  in the growth of the plant. They are of three
  types.
• i) Apical meristematic tissues - are present
  in the tips of stems and roots.
• They help in the growth of stems and roots.
• ii) Lateral meristematic tissues - are
  present in in the sides of stems and
• roots. They help to increase the girth of
  the stems and roots.
• iii) Intercalary meristematic tissues - are
  present at the base of leaves and
• internodes and help in the growth of those
  parts.

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b) Permanent tissues -

• Permanent tissues are formed from
  meristematic tissues. They do not divide
• and have permanent shape and size. They
  differentiate into different types of
• permanent tissues. Permanent tissues are of two
  main types. They are Simple
• permanent tissues and Complex permanent tissues.
• i) Simple permanent tissues - are made up of one
  type of cells. They
• are of three types called Parenchyma,
  Collenchyma and Sclerenchyma.
• Parenchyma - consists of loosely packed thin
  walled cells having more
• intercellular spaces. Some parenchyma cells in
  leaves contain chloroplast
• and prepares food by photosynthesis. Some
  parenchyma cells have large air
• cavities which help the plant to float on
  water. Some parenchyma cells of
• roots and stem store water and minerals.
• Collenchyma - consists of elongated cells
  having less intercellular spaces
• and thicker at the corners. They give
  flexibility and allows easy bending of
• different parts like stem, leaf etc. They also
  give mechanical support to the
• plant.
• Sclerenchyma - consists of long, narrow, dead
  thick walled cells. The cell
• walls contain lignin a chemical substance
  which act like cement and hardens
• them. It gives strength and hardness to the
  plant parts.

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Parenchyma
Collenchyma
Sclerenchyma
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• ii) Complex permanent tissues - are made up of
  more than one type
• of cells. There are two types of complex
  tissues. They are Xylem and Phloem. They are
  called vascular or conducting tissues.
• Xylem - consists of tracheids, vessels,
  xylem parechyma and xylem fibres.
• The tracheids and vessels help to transport
  water and minerals from roots
• to all part of the plant. Xylem parenchyma
  stores food and fibres help in
• support.
• Phloem - consists of sieve tubes, companion
  cells, phloem parenchyma and
• phloem fibres. The sieve tubes and companion
  cells transports food from
• leaves to all parts of the plant. Phloem
  parenchyma stores food and fibres
• help in support.

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4) Animal tissues -

• Animal tissues are of four main types . They
  are - Epithelial tissue, Muscular tissue,
  Connective tissue and Nervous tissue.
• i) Epithelial tissues - are of different
  types. They are - Squamous, Columnar,
• Cuboidal, Glandular etc.
• ii) Muscular tissues - are of three types.
  They are - Striated, Unstriated and
• Cardiac.
• iii) Connective tissues - are of different
  types. They are - Blood, Bone,
• Ligaments, Tendons, Cartilage, Areolar,
  Adipose etc.
• iv) Nervous tissue - consists of nerve cells
  called neurons.
• 
  Animal tissues
• Epithelial tissue Muscular tissue
  Connective tissue Nervous tissue
• Squamous Striated
  Blood
• Columnar Unstriated
  Bone
• Cuboidal Cardiac
  Ligaments
• Glandular
  Tendons
• 
  Cartilage
• 
  Areolar
• 
  Adipose

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a) Epithelial tissue -

• Epithelial tissue is the covering or
  protective tissue in animals. It forms the outer
  covering like skin, outer covering of organs,
  inner lining of blood vessels, lungs, oesophagus,
  etc. It protects the body and controls the
  movement of materials between the body and the
  surroundings and between the parts of the body.
  The cells are closely arranged and have a fibrous
  basement membrane.
• i) Squamous epithelial tissue - consists of a
  layer of thin flat cells. It is
• present in the linings of blood vessels,
  lungs, mouth, oesophagus etc. The
• skin has several layers of epithelial
  cells. This tissue is called Stratified
• squamous tissue.
• ii) Columnar epithelial tissue - consists of
  tall pillar like cells. It is present in
• the walls of the intestine. The columnar
  epithelial tissue in the respiratory
• tract has hair like projections called
  cilia. This tissue is called Ciliated
• columnar epithelial tissue.
• iii) Cuboidal epithelial tissue - Consists of
  cone shape cells having a basement
• membrane. It forms the lining of kidney,
  tubules and ducts of salivary glands
• and provide mechanical support.
• iv) Glandular epithelial tissue - Sometimes
  epithelial tissue folds inwards and
• forms a multicellular gland which secretes
  substances. This tissue is called
• Glandular epithelial tissue.

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b) Muscular tissue -

• Connective tissue helps in the movements of
  the body. It consists
• of elongated cells called muscle fibres. It
  contains a protein called
• contractile protein which contracts and relaxes
  and helps in
• movements. Muscles which can move under our will
  are called
• voluntary muscles. Muscles which do not move
  under our will are
• called involuntary muscles.
• i) Striated muscles - are voluntary muscles
  having light and dark
• striations. The cells are long, cylindrical
  and are multinucleated.
• They are also called skeletal muscles
  because they are attached to
• bones. They help in voluntary movements of
  the body.
• ii) Unstriated muscles ( Smooth muscles) - are
  involuntary muscles
• having no striations. The cells are long and
  spindle shaped and are
• uninucleated. They are present in alimentary
  canal, blood vessels,
• bronchi of lungs, iris of eye etc. They help
  in involuntary
• movements.
• iii) Cardiac muscles - are involuntary muscles
  having faint striations.
• The cells are long, cylindrical, branched
  and multinucleated. They
• are present in the heart and helps in the
  contraction and relaxation
• of the heart.

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c) Connective tissue -

• Connective tissue connects and joins the
  different parts of the body
• together. The cells of the connective tissue are
  loosely packed and the space between the cells
  are filled with a jelly like matrix.
• i) Blood - Blood contains a fluid matrix
  called plasma which
• contains red blood cells (RBC), white blood
  cells (WBC) and
• platelets. The blood transports gases,
  digested food, hormones,
• waste materials etc.
• ii) Bone - is a hard and strong tissue. It
  consists of cells which are
• embedded in a hard matrix containing calcium
  and phosphorus
• compounds. Bone forms the framework of the
  body and supports
• the body and the main organs.
• iii) Ligaments - are flexible tissues which
  joins bones together and
• helps in movements.
• iv) Tendons - are fibrous tissues which joins
  muscles to bones and
• helps in movements.
• v) Areolar tissues - fills the space between
  skin and muscles, inside
• the organs, around blood vessels etc. It
  helps to repair the tissues.
• vi) Adipose tissue - is found below the skin and
  between internal
• organs. It contains fats and helps to store
  fats.

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COMPONENTS OF BLOOD
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LIGAMENTS AND TENDONS
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• Aerolar tissue
  Adipose tissue
• Bone tissue
  Cartilage tissue

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d) Nervous tissue -

• Nervous tissue helps to carry messages from
  one part of the body to the other and responds to
  stimuli. It is found in the brain, spinal cord
  and nerves. It consists of nerve cells called
  neurons.
• Neuron (Nerve cell) - has a cell body
  containing a nucleus and cytoplasm. It has hair
  like structures called dendrites and a long part
  called axon having nerve endings. The axon has a
  protective covering called myelin sheath. The
  neurons are joined together to form nerve fibres.
  The junction between two neurons is called
  synapse.